Inclosed fuse.



R. '0'. COLE. INOLOSED FUSE. APPLICATION FILED MAB.13, 1909. RENEWEDJAN. 4, 1912.

1,025,247. Patented May 7, 1912.

BDBERT C. COLE, OF WEST HARTFOBD, CONNECTICUT, ASSIGNOR TO THE JOHNS-PRATT COMPANY, OF HATE/TR13, CONNECTICUT, A CORPORATION 01E CONNECTICUT.

ENCLOSED FUSE.

Application filed March 13,- 1909, Serial No. 483,249.

To all whom it may concern Be it known that 1, ROBERT C. Conn, a citizenof the United States, residing at West Hart-ford, in the county ofHartford and State of Connecticut, have invented certain new and usefulImprovements in Inclosed Fuses, of which the following is a full, true,and concise specification.

This invention is an improvement in the construction of inclosedelectric fuses, and particularly in fuses of the type which employs afilling of comminuted non-conducting material around the inclosedfusible medium, and consists in the construction and disposition of suchfusible medium in the form 'of thin sheets or strips connecting theterminals of the device, as hereinafter described, whereby the rigidityand durability of the structure is promoted and a maximum extent ofsurface area is provided, having effective contact with the fillingmaterial at all points.

The invention also involves incidental features of construction andarrangement contributing toward the result just stated, but also usefulin other relations, as will be apparent from the following descriptionand as more particularly pointed out in 3 comprises the claims.

Referring to the sheet ofdrawings constituting a part hereof, Figure 1is a longitudinal section, with parts in elevation, of an inclosed fuseembodying my invention; Fig. 2 is an enlarged detail of the conductingelement thereof, with parts in central section; Fig. 3 is across-section of Fig. 1 on the line 33; and Fig. 4 is a longitudinalcentral section, with parts in elevation, of a modified form. Theinclosed fuse illustrated in Figs. 1 to a tube or casing 1 of fiber or"other non-conducting material provided with ferrules 2 at its oppositeends and constituting an inclosure for a mass of filling material Thisfilling material may consist of slaked-lime, g psum, or anyothersuitable non-conducting material or composition in comminutedform,as customarily employed in the manufacture of inclosed fuses. Theinclosure contains two fuse link terminals 4, suitably supported withinthe casing, and extending to or connected with the exterior 9ftheferrules, whereby they may be electrically connected with theterminals of the circuit in which the device is Specification of LettersPatent.

parallel with Patented May t, 1912;

Renewed January 4, 1912. Serial No. 669,438.

to be employed. In the form taken for illustration, the terminals areround rods held in central apertures in the ferrules, which latter areof metal, and either the projecting ends of the rods or the ferrules, orboth, may be secured in contact with the circuit terminals, according tothe type of the latter. The proximate ends of these rods or terminals,within the casing, are joined by the fusible medium, consisting, asabove stated, of a plurality of strips or flat fuse links 6 adapted tomelt and open the circuit upon the passage therethrough of a current ofabnormal conditions. The two terminals and the fusible medium constitutetogether the conducting element of the device through which the currentpasses from one end to the other, and in the manufacture of inclosedfuses, it is customary for these or equivalent parts to be separatelyassembled and introduced as a whole into the interior of the casing,which is then filled with the filling material and closed withtheferrules.

The fusible medium, being of metal which has a low melting point andbeing also frequently weakened by calibration notches orperforations,-as shown at 6 forms'a somewhat fragile connection betweenthe terminals, so that theconducting element is quite liable to injury.or mechanical rupture either during the process of its assemblage orafterward, when it is inclosed within the casing, and the resultingstructure becomes defective or impaired in value as a consequence. Thisis particularly likely to occur with multiple strips where injury to oneof the group is aptto escape notice. This invention seeks to overcome orreduce the ob jection due to this cause, by the construction of thefusible medium out of sheet metal having three or more flat orsubstantially flat and. straight members or fuse links, which aredisposed in intersecting planes, the axisv of the device and directlyand rigidly secured at their ends to the-proximate ends of the fuse linkterminals. The latter are provided with lateral enlargementain the shapeof circular disks 5 opposing each other, and the several flat strips 6are soldered in butt contact with the faces of these disks, as indicatedin the drawing, so that one or more of such strips will offer itsedgewise resistance, and hence its greatest resistance, to lateralstrains in any direction in the conducting 110 element, thereby enablingthe assembled terminals and fusible links to be handled freely andrapidly without danger of fracture. The resulting structure possessesremarkable'rigidiqy even when the fusible medium is constructed ofextremely thin strips.

In the preferred form the disks 5 are cupshaped, as shown, and the endsof the flat strips are embedded in a mass of solder con tained Withinthe cup, thereby. readily forming a secure mechanical connection with anadequate electrical continuity between said strips and the terminals,but othrr modes of connection may be employed Provided all of the stripsor facesare connected directly to the common rigid terminal such asafforded by the disk and the solder. The disposition of the multipleflat strips with their flat faces in intersecting or radial planesprovides between them a series of inwardly converging, wedge-shapedspaces into which the filling material will readily find its way whenintroduced through the end of the casing, so that com plete effectivecontact of the filling material against the entire exposed surface ofthe fusible medium is thereby insured in a most compact and efficientmanner. A strictly radial arrangement of the strips, as shown in thedrawing, is preferred.

The modified form of Fig. 4 includes with the structure above. describeda supplemental casing or sheathing 8, made preferably of asbestos, whichsurrounds the fusible links and fits snugly over the periphery of thecircular disks 5, thus forming with them an interior and auxiliaryinclosure for the fusible medium, which is useful under some conditionsfor confining and stifling the force of the disruption, as will beunderstood by those skilled in this art.

I claim the following:

1. A conducting element for inclosed fuses comprising two fuse-linkterminals provided with cup-shaped disks at their inner extremities anda plurality of separate, straight, flat'fu'se links arranged in radialpositions with respect to the axis of said terminals and connecting saiddisks in multiple relation and embedded at their extremities in aconducting material contained within said cup-shaped disks. 7

2. An inclosed fuse comprising a casing containing a plurality of fuselinks formed oi fiat, straight strips of fusible material arranged inmultiple relation and in substantially radial posit-ions with respect tothe axis of the fuse, and two fuse link terminals each provided withalateral enlargement at its inner end, to each of which enlargements theends of said radially arranged links are directly and rigidly con-'nected, thereby forming a rigid conducting element for insertion withinthe fuse casing.

3. In an inclosed fuse, a casing containing fuse-link terminalsprovided'with disks at their inner extremities, and a plurality ofseparate fuse-links secured to and connecting said disks, in combinationwith an insulating sleeve surrounding said disks and forming therewithan inclosure for said fuse-links.

In testimony whereof, I have signed my name to the specification in thepresence of two subscribing witnesses.

.ROBERT C. COLE.

Witnesses:

ARTHUR B. Pinon, ALVAN WALDO HYDE.

